$.ajaxSetup( {
	//设置ajax请求结束后的执行动作
	complete : 
	function(XMLHttpRequest, textStatus) {
		// 通过XMLHttpRequest取得响应头，sessionstatus
		var sessionstatus = XMLHttpRequest.getResponseHeader("SESSIONSTATUS");
		if (sessionstatus == "TIMEOUT") {
			var win = window;
			while (win != win.top){
				win = win.top;
			}
			win.location.href= XMLHttpRequest.getResponseHeader("CONTEXTPATH");
		}
	}
});